More than half the species of wading birds in Europe, Africa and west Asia are declining in numbers more steeply than ever, conservationists have warned.

Water birds such as lapwings, plovers, godwits and curlews undertake long distance migrations from breeding grounds as far north as the Arctic to wintering areas as far away as South Africa.

Many congregate in huge numbers in only a few sites, making those areas critical to the birds' survival, according to Wetlands International which drew up the newly-launched atlas of key sites for waders.

While species and their habitats are protected in Europe, there needs to be better protection of key wetlands along the migration routes of the birds, particularly in Africa and the Middle East, Wetlands International said.

A string of wetlands on the western coast of Africa, along the Senegal and Niger rivers and around Lake Chad, and in east Africa along the Rift Valley and coasts, is crucial for many migratory waders, the organisation said.

But these wetlands, and others in Asia, are under huge pressure from irrigation schemes, conversion to farming and development.

For example, the Tana River Delta in Kenya is under threat from conversion sugar cane plantations and damage to the one site would hit resident birds and the survival of migratory birds whose ranges stretch from Siberia to southern Africa.

In some places the birds themselves are extensively hunted.

Wader Atlas author Simon Delany, said: "Waders such as the ruff are heavily protected in the EU; farmers receive thousands of euros for nest protection.

"These same birds are for sale in the markets of Mopti, Mali, for just 25 cents each.

"If just a part of the finance available in the EU for waterbird protection were to go to the areas where these same birds winter a huge difference could be made."

The Wader Atlas, launched at a Joint Nature Conservation Committee (JNCC) event in London today, identifies 876 key sites including lakes, coastal areas and floodplains for 59 of the 90 wading bird species found in countries covered by a UN agreement on migrating waterbirds.

It highlights 68 sites where five or more species gather in "internationally important" numbers – with more than 1 per cent of the global population congregating there.

There are 112 sites identified in the atlas, which was part-funded by the UK Government, where more than 40,000 waders have been counted.

Wetlands International and its specialist study group, the International Wader Study Group, hope the atlas will provide the necessary information for conservation of wading species in Europe, Africa and west Asia.

The JNCC is holding today's conference following a number of international meetings on conservation.

The conference is looking at themes including tackling threats from alien species and emerging wildlife disease, the impacts of climate change and expanding markets for biofuels and how best to support conservation in the UK's Overseas Territories and Crown Dependencies.